When it comes to Subway sandwiches, we always thought that if you find a variation that works for you, stick with it. But news out of the Subway camp has us thinking otherwise -- there are apparently 37 million possible sandwich variations at the chain's nearly 38,000 locations.

That's a lot of sandwiches. In all, Subway serves about 2.6 billion sandwiches a year -- so does that mean every sandwich variation has been ordered at least once?

The behemoth chain employs about 380,000 people across 100 countries, and ingredients aren't the same across the board. Although the core menu is similar pretty much everywhere, some regions require special tweaks.

In a release, Subway explains one such change:

The first Subway restaurant outside of the U.S. opened in the Middle Eastern nation of Bahrain in 1984. In accordance with local customs, the food at restaurants in the region is Halal, meaning that pork products are not served and items such as ham and bacon are substituted by similar offerings made from lamb, chicken or turkey.

About half of Subway's 2,000 new locations this year were in international markets, so knowing the culture, religious traditions and preferences of those places is crucial.

In India, for instance, no beef or pork is served to accomodate the large Muslim and Hindu populations. Subway recently launched several vegetarian-only restaurants to attract those demographics.

Subway is hardly the only restaurant chain to cater to local tastes. McDonald's recently announced it would also open a string of vegetarian restaurants in India.

Click through the below gallery for more Subway offerings from around the more.

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  • Sweden: Skagenrora

    A mix of shrimp, crab, mayo, lemon, herbs and spices.

  • India: Paneer Tikka

    Marinated cottage cheese slices cooked in a traditional Indian clay oven.

  • India: Corn and Pea

    A blend of corn, peas and carrots in a mayonnaise based sauce.

  • India: Chicken Seekh

    Coarsely ground barbeque chicken seasoned with mint leaves and green chilies.

  • Brazil: Smoked Chicken and Cream Cheese

    This sandwich is similar to chicken salad, but it's made with cream cheese instead of mayonnaise.

  • Japan: Shrimp and Broccoli Sandwiches

  • Japan: Bacon, Potato and Anchovy Sauce

  • Japan: Spanish Omelette

  • Mexico: Pierna Habanera

    Spicy ham served with Mexican-style cream and hot habanera sauce.

  • South Africa: Peri Peri Chicken

    Chicken strips with an African-inspired sauce seasoned with chili peppers.

  • Saudi Arabia: Halloumi

    Halloumi is a soft white cheese made from sheep and goat milk. It has a high melting point and is typically grilled or fried.

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